Stubby stops resolving after some time (19.07 snapshot)

Hi, everyone,

Yeah, something seems to have gone horribly wrong with stubby/getdns(_query). It basically stops resolving DNS queries after about an hour. Moreover, calling getdns_query always results in this message…

root@apu:~# getdns_query 
An error occurred: 301 'The context has internal deficiencies'

… even during the short time stubby is working correctly.
This is on an amd64 machine running a custom built (with the image builder) image. I believe this could be an OpenSSL configuration problem, since another machine (ath79) running OpenWrt built from scratch seems to work fine.
Does anyone have any idea about what might be causing this?